The internal combustion engine works by burning a pre-prepared mixture of air, oil and gasoline. Adjusting the carburetor chainsaw needed to prepare the mixture in the required proportions. From the work of the carburetor depends on whether the engine will work with the stated power or stalls.
The principle of the carburetor
Regardless of the manufacturer’s company, the principle and order of operation of the carburetor of internal combustion engines is the same.
For mixing air and fuel, the carburetor is a device that includes:
- constriction air tube;
- fuel supply system;
- regulating choke.
Air under atmospheric pressure, passing the air cleaner, is supplied to the zone of constriction, where its flow is regulated by a flat valve that covers the cross section. After narrowing in the pipe there is a discharge. As a result, the vacuum sucks fuel from the fuel supply tube, the output of which is regulated by a fuel needle connected by a jet to the float chamber. The device of the carburetor chainsaw in principle does not differ from other mixers of fuel of internal combustion engines.
The principle of mixing is to regulate the air damper, the level of the float, depending on the degree of vacuum. Open the air. more fuel flows, the engine increases speed. The correct ratio of combustible mixture depends on the fine adjustment of the carburetor chainsaw. If there is a lot of air in the fuel, the power drops, the mixture is called depleted. With a lack of air there is a large fuel consumption, incomplete combustion, carbon deposits on the cylinder and the exhaust of unburned fuel. It says the mixture is supersaturated.
The Urals chainsaw, according to the instructions, requires running in using an enriched fuel mixture. Therefore, the carburetor from the factory comes with a setting for the period of running. When switching to the operating mode, the node is reconfigured.
Signs of good performance carburetor chainsaws:
- the engine runs smoothly, reminiscent of the four-stroke sound;
- quick turnaround;
- at idle the chain does not scroll.
When carburetor tuning is required
New chainsaw adjusted to the recommended mix. It will only require fine-tuning with the help of three screws; you do not need to disassemble the carburetor.
Purpose of adjustment screws:
- “L” regulates fuel delivery at low revs;
- “H” is needed to regulate the maximum fuel supply;
- “T” idle control.
Since the carburettor adjustment of the saw occurs by ear when the engine is running, it is necessary to observe safety measures. The saw must be positioned steadily with cutters pointing in a safe direction.
Before the beginning of the manipulations, it is necessary to mark the initial position of the screws with a paint or felt-tip pen. The exact setting values of the carburetor chainsaw for each model are in the instruction manual.
However, more often you need a carburetor tincture after eliminating the malfunction of the tool. The reasons may be:
How to adjust the carburetor on the chainsaw specific model? Perform successive operations, guided by the instructions. Here is the algorithm, the general sequence of actions.
There are two stages of configuration:
- basic, with the engine off;
- thin. on a warm engine, in work at idle.
The basic setting is carried out only for fuel supply screws at low and high rpm. Smoothly slowly, you should completely shut off the flaps until it stops. Also smoothly turn counterclockwise both screws 1.5 turns. After that, start the engine and warm it up for 10 minutes.
How to set up a carburetor on a chainsaw with the engine running:
- adjust the idle speed with the “T” screw, by turning it counterclockwise until the engine is stable at idle;
- check the speed of the set of turns, with a slow promotion, turn the screw L 1/8 of a turn extra;
- set the maximum speed of rotation on the tachometer with the screw H;
- Check the operation of the carburetor at idle finally.
How to find a carburetor malfunction
However, the adjustment may be preceded by the repair of the carburetor itself, when it cannot fulfill its function of the fuel mixer.
If the fuel for some reason does not enter the engine, you need to check the status of the fuel supply unit. Often the cause is the supply of poor-quality gasoline, as a result of clogged fuel passages.
If the mixture of fuel has stood for a long time, the additives have collapsed, the mixture can clog the sludge moves, the grid. In this case, a long flush is required, which is done with solvents in a service workshop.
If the removal of the malfunction is carried out with your own hands, you need to free up space and decompose small parts.
Need a tool:
- screwdriver for cross-threaded heads;
- socket wrench or M6 head;
- clean gasoline.
The main thing is to properly release the node from the installation site, cleaning it from the outside of dirt. The air intake is removed, opening access to the carburetor and suction draft. Remove the accelerator lever by lowering the carburetor flap. To release a detail, having removed the suction lever, having lifted on itself a wire together with the lever, having hooked on the left.
Flush the carburetor in gasoline, purge it with air, clean the grille, making the injection a fine needle.
Assembling the knot in reverse order, you should make sure that the spring under the needle lever is put in place. If you forget it, the fuel is not cut off, the candle is damp and does not give a spark.
It happens, on the saw Stihl key gas slightly wedges. In this case, it is necessary to clear the throttle from plaque. After cleaning it is necessary to protect the valve by tinning.
Having collected the carburetor, setting it in place, make the adjustment, as described above.